A single 8 pin connector is rated for up to around 300-320 watts.
The 7950x can consume up to 250-260 watts, if you cool it properly. If you try to overclock it, it will consume even more.
While technically this 250 watts is below the rating of the single 8 pin CPU connector, it's highly recommended to use both cables and connectors because you'll reduce the "stress" on the connectors and headers on the motherboard - the connectors and headers will heat less, and there's gonna be less losses in the wires between the power supply and the motherboard.
You don't "overvolt" the processor by connecting more wires. You just add more wires, meaning each wire and each pin in the connectors and headers has to carry less power, which means happier components.
You have 6 (SIX) headers on the motherboard power supply, the three above the text saying 6+2 PCI-E & 4+4 CPU , and the three under it. They can be used either for video cards, or to power CPUs. You don't need to use exactly those two you circled. In fact, it would probably be just a very very tiny bit better to have one cable plugged a bit further away from the first cable - leave one column of headers empty on the power supply.